Yue Lisha, Wang Yue, Cui Zijian, Zhang Xiaoju, Zhu Yongqiang, Zhang Xiang, Chen Suguo, Wang Xinmei, Zhang Kuang
Opt Express. 2021 Apr 26;29(9):13563-13575. doi: 10.1364/OE.423256.
Perfect metasurface absorbers play a significant role in imaging, detecting, and manipulating terahertz radiation. We utilize all-dielectric gratings to demonstrate tunable multi-band absorption in the terahertz region. Simulation reveals quad-band and tri-band absorption from 0.2 to 2.5 THz for different grating depths. Coupled-mode theory can explain the absorption phenomenon. The absorption amplitude can be precisely controlled by changing the pump beam fluence. Furthermore, the resonant frequency is sensitive to the medium's refractive index, suggesting the absorber may be of great potential in the sensor detection field. The experimental results exhibit a high detectivity of pesticides.
完美超表面吸收器在太赫兹辐射的成像、探测和操控中发挥着重要作用。我们利用全介质光栅展示了太赫兹波段的可调谐多波段吸收。模拟结果表明，不同光栅深度下，在0.2至2.5太赫兹范围内存在四波段和三波段吸收。耦合模理论可以解释这种吸收现象。通过改变泵浦光束通量，可以精确控制吸收幅度。此外，共振频率对介质折射率敏感，这表明该吸收器在传感器探测领域可能具有巨大潜力。实验结果显示出对农药的高检测率。
